An Amplified Indoor TV Antenna

I was given an antenna by a family member who didn't want it any longer: It is the RCA, ANT 140. The label said: Thomson Consumer Electronics, Deptford NJ 08096-2088. I don't know who the real manufacturer was, but it was made in China.

I don't know if they are one and the same company who designed this small amplified indoor TV-FM antenna. My guess is that it was Thomson that designed and had it manufactured.

Editor's note: Thomson is one of the companies that have the right to manufacture under the RCA name. There are several.

I figured this would be a good antenna to test this winter. It is an indoor antenna so I decided to test it in my living room. The windows face south towards Washington, D.C., with Baltimore to the east.

The test consisted of placing the antenna in the window about half-way up, where the two halfs of the window come together. I located a station, ChV 24, and then adjusted the amplifier gain to test the best reception. I found that when too low, the station dropped out; too high also caused problems. It received this station best when the gain was adjusted between those two bad points.

I also tested the simple 4" non-adjustable antenna that came with the portable 7" AUVIO HDTV I bought shortly after the FCC mandate to switch to all HDTV programming. It came with two un-amplified antennas, a small fixed-length antenna of about 4" high, and a telescoping antenna. I used only the small 4" antenna for these tests since I could not change the length of the RCA antenna.

The standard bowtie antenna was also used putting it as close to the same height as the other antennas as I could get it.

The single bowtie antenna is my “standard” used to test other antennas against. It is then a simple matter to see if the antenna being tested gets more or fewer stations than this standard antenna. The stations the standard bowtie antenna received were:

12 (41) NOTE: Some of these are perfect duplicates, MPT stations for instance.

The small 4" antenna received 5 channels, ChV: 2, 4, 20, 24, and 45.

The RCA amplified antenna only received one channel: ChV 24.

The RCA amplified-antenna reception was very disappointing. I thought that perhaps it was damaged by the original owner.

Still, as can be seen by the reception data of the three antennas, the home-brewed simple bowtie antenna was far superior to both the simple 4" antenna and the amplified antenna.

I took the RCA antenna apart to see if the antenna was obviously damaged, and found that the antenna was a long piece of coiled wire. No damage to the antenna or circuit was observed.

In the photo above it can be seen that a piece of coax with alligator clips was used to attach just the RCA coiled antenna to the TV. I tested the basic antenna without the amplifier and found that it received the following stations: ChV: 2, 11, 24, 45, and 54. These weren’t exactly the same stations as the four inch antenna but it was still much better than it did when the amplifier was included: five stations compared to only one with the amplifier.

I thought that there were two possible explanations for the poor response of the antenna-plus-amplifier. As stated before, perhaps the amplifier was defective. The other possibility – which, knowing the TV antenna problems in this location, seemed more likely - is that the signals are borderline to begin with and the added noise from the amplifier caused these marginal signals to drop below the noise level.

In an attempt to figure this out, I decided to use the Digiair TV Antenna/Signal Analyzer.

The DTV and the Digiair Analyzer were again used but this time with an antenna switch. The two inputs were from the coax going directly to the antenna and the other was to the coax coming from the amplifier. This arrangement allowed switching between the antenna and the antenna-plus-amplifier to see the differences between the signals using either the TV or the analyzer. The results were not as clear cut as I hoped they would be. I also found that the amplifier gain should be adjusted to right before the red LED comes on.

The second day the antenna and antenna-plus-amplifier were giving better results. The antenna-plus-amplifier was able to receive four stations and the antenna alone was able to receive eight stations. This time, the antenna-plus-amplifier received ChVs: 2, 24, 45, and 54. The antenna alone received ChVs: 2, 5, 11, 14, 20, 24, 45, and 54.

One thing that was clear, and expected, was that, with the amplifier, the Signal-to-Noise was lower by 3 to 6 dBuV.

The Digiair for the original five stations showed that ChV 2 S/N was 24 vs. 18 for the antenna vs the antenna-plus-amplifier. ChV 54 S/N was 21 and 18 for the antenna vs the antenna-plus-amplifier. What still has me stumped is that the other three stations showed ChVs: 11, 24, and 45, with S/Ns of: 24, 24, and 19 for just the antenna. The Digiair was unable to display the S/Ns, BERs, and MERs. The Signal levels were ChVs: 11, 24, 45 at: 54, 54, and 49 dBuV for the antenna and 31, 42, and 38 dBuV for the antenna-plus-amplifier.

While the antenna-plus-amplifier was not as bad as I originally thought, the basic antenna is still better, and neither is as good as a simple, unamplified bowtie antenna.

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